Strip out control codes from the logged messages (#10081)

* Strip out control codes from the logged messages

* Also strip away C1 control codes

* Add extra comments

* Clear the buffer after flushing; rename `write` to `flush`

* Move control code stripping into its own function

* Also strip out control codes from panic messages

* Also strip out Unicode left-to-right/right-to-left control codes

substrate/primitives/panic-handler/src/lib.rs

@@ -25,6 +25,7 @@
 //! temporarily be disabled by using an [`AbortGuard`].
 
 use backtrace::Backtrace;
+use regex::Regex;
 use std::{
 	cell::Cell,
 	io::{self, Write},
@@ -125,6 +126,24 @@ impl Drop for AbortGuard {
 	}
 }
 
+// NOTE: When making any changes here make sure to also change this function in `sc-tracing`.
+fn strip_control_codes(input: &str) -> std::borrow::Cow<str> {
+	lazy_static::lazy_static! {
+		static ref RE: Regex = Regex::new(r#"(?x)
+			\x1b\[[^m]+m|        # VT100 escape codes
+			[
+			  \x00-\x09\x0B-\x1F # ASCII control codes / Unicode C0 control codes, except \n
+			  \x7F               # ASCII delete
+			  \u{80}-\u{9F}      # Unicode C1 control codes
+			  \u{202A}-\u{202E}  # Unicode left-to-right / right-to-left control characters
+			  \u{2066}-\u{2069}  # Same as above
+			]
+		"#).expect("regex parsing doesn't fail; qed");
+	}
+
+	RE.replace_all(input, "")
+}
+
 /// Function being called when a panic happens.
 fn panic_hook(info: &PanicInfo, report_url: &str, version: &str) {
 	let location = info.location();
@@ -139,6 +158,8 @@ fn panic_hook(info: &PanicInfo, report_url: &str, version: &str) {
 		},
 	};
 
+	let msg = strip_control_codes(&msg);
+
 	let thread = thread::current();
 	let name = thread.name().unwrap_or("<unnamed>");
 
@@ -181,4 +202,44 @@ mod tests {
 		let _guard = AbortGuard::force_abort();
 		std::panic::catch_unwind(|| panic!()).ok();
 	}
+
+	fn run_test_in_another_process(
+		test_name: &str,
+		test_body: impl FnOnce(),
+	) -> Option<std::process::Output> {
+		if std::env::var("RUN_FORKED_TEST").is_ok() {
+			test_body();
+			None
+		} else {
+			let output = std::process::Command::new(std::env::current_exe().unwrap())
+				.arg(test_name)
+				.env("RUN_FORKED_TEST", "1")
+				.output()
+				.unwrap();
+
+			assert!(output.status.success());
+			Some(output)
+		}
+	}
+
+	#[test]
+	fn control_characters_are_always_stripped_out_from_the_panic_messages() {
+		const RAW_LINE: &str = "$$START$$\x1B[1;32mIn\u{202a}\u{202e}\u{2066}\u{2069}ner\n\r\x7ftext!\u{80}\u{9f}\x1B[0m$$END$$";
+		const SANITIZED_LINE: &str = "$$START$$Inner\ntext!$$END$$";
+
+		let output = run_test_in_another_process(
+			"control_characters_are_always_stripped_out_from_the_panic_messages",
+			|| {
+				set("test", "1.2.3");
+				let _guard = AbortGuard::force_unwind();
+				let _ = std::panic::catch_unwind(|| panic!("{}", RAW_LINE));
+			},
+		);
+
+		if let Some(output) = output {
+			let stderr = String::from_utf8(output.stderr).unwrap();
+			assert!(!stderr.contains(RAW_LINE));
+			assert!(stderr.contains(SANITIZED_LINE));
+		}
+	}
 }